Multi-chambered tubes for the simultaneous delivery of different substances when the tube is squeezed have previously been known. Concentric type tubes, in which chambers of generally circular cross section and of approximately equal volume are provided one within the other, as well as side by side type tubes, in which the chambers are generally adjacent to each other, have been proposed. In either case, achieving a simultaneous dispensing of each component from the tubular container that is uniform, regardless of where and how the container is squeezed, remains problematic. Another continuing problem is providing an attractive presentation of a dispensed multi-component composition contained in such a tube.
The amount of material dispensed from each chamber of a multi-chambered tube is dependent upon the decrease in volume of the chamber occasioned by the deformation of the walls of the chamber. This deformation, and thus the amount of material dispensed, depends upon several factors including the relative viscosities of the substances to be dispensed, the size and shape of the orifice(s) through which the substances are dispensed, the pressure applied to the tube, and the configuration of the tube and chambers. Concentric chambered tubes are generally believed to be less desirable as compared to side by side chambered tubes due to the increased skin friction seen by the composition in the outer chamber of a concentric tube that results from increased contact with the outer wall of the inner chamber.
U.S. Pat. No. 5,927,550, “Dual Chamber Tubular Container,” issued to Mack et al. on Jul. 27, 1999 discloses a side by side tubular container having a dividing wall that is attached longitudinally to the tubular chamber sidewalls. The plane of the divider wall of the dispensing exit is offset from the plane of the crimp seal at the bottom of the tube preferably by about 90°. Other previously described tubular containers include those in which the crimp seal and the exit divider wall are in the same plane, e.g., U.S. Pat. Nos. 1,894,115 and 3,788,520; and German patent no. 2017292.
However, the tubular container described in the above-mentioned Mack et al. US patent is believed to be difficult to manufacture in terms of attaching the dividing wall to the tubular chamber sidewalls, and further in terms of connecting the dividing wall of the tube to the injected molded dividing wall of the tube shoulder. Thus, this tube is not believed to be easy or cost-effective to manufacture.
U.S. Pat. No. 5,954,234, “Uniform Dispensing Multichamber Tubular Containers,” WO 97/46462, “Codispensing of Physically Segregated Dentifrices at Consistent Ratios,” and WO 97/46463, “Uniform Dispensing Multichamber Tubular Containers,” each describe a multichamber container in which the outer walls and inner divider walls have specified physical characteristics. The inner partition wall of this tube shifts laterally to respond to compressive displacement of the outer walls of the tube during squeezing. This partition wall is therefore made as thin and flexible as possible.
It is believed that uniformity of dispensing from this tube is less than ideal because the inner divider wall is thin and soft, thus making it difficult to build required pressure in the chambers to maintain even dispensing of a product, especially if the component compositions of the product are of greatly different relative rheologies and viscosities. Further, this tube has no device for flow regulation, making it difficult to maintain an even volume change across the chambers upon dispensing.
Based on the foregoing, there is a continued need for a multi-chambered dispensing tube that can consistently deliver the same amount, shape, and size of the component compositions contained in each chamber at the same dispensing rate, regardless of how the tube is squeezed. There is also a need for such a tube to be cost effective and easy to manufacture. None of the existing art provides all of the advantages and benefits of the present invention.